Vertically stable articulator having dual struts

ABSTRACT

A dental articulator structure for use in registration of a pair of casts of a dental model which are positioned in an opposing and spaced relationship. The articulator structure includes at least one axially rigid support member having opposing ends from which multi-piece cast attachment members may be orthogonally attached. The at least one axially rigid support member and the orthogonally attachable cast attachment members being an articulator structure that locates the axially rigid support member substantially close to the back molar face of the opposing pair of dental model casts such that confronting translational movement of the dental model casts is prevented in a plane parallel to the axially rigid support member, especially confronting translational movement in a region where back molars may be missing in a dental model. The multi-piece cast attachment structure is formed having mating curved, partially spherical, surfaces that facilitate multi-directional alignment of the pair of opposing dental model casts. The multi-piece cast attachment structure may be formed as a tandem arrangement that includes a two-piece attachable alignment structure in combination with at least one spacer block that compensates for cast size differences and is attachable to the back face of a selected cast. In a preferred embodiment, the at least one axially rigid support member is formed as a U-shaped structure defining a pair of axially rigid support arms.

RELATED APPLICATIONS

This application is related to U.S. Patent Applications being filed onthe same date by the same inventor entitled: "VERTICALLY RIGID DENTALARTICULATOR SYSTEM AND METHOD", having Ser. No. 08/469,450 filed on Jun.6, 1995, now U.S. Pat. No. 5,766,007, "DENTAL MODEL CAST MOUNTINGBLOCK", having Ser. No. 08/467,448 filed on Jun. 6, 1995, now U.S. Pat.No. 5,868,569, and "SPACER BLOCK FOR A DENTAL ARTICULATOR" having Ser.No. 08/467,453 filed on Jun. 6, 1995, now U.S. Pat. No. 5,800,166.

FIELD OF THE INVENTION

This invention relates to dental articulators. More particularly, thepresent invention relates to dental articulators for use in registrationof dental model casts positioned in opposing and spaced relationship.Even more particularly, the present invention relates to dentalarticulators, for use in registration of dental model casts havingnon-uniform bite in a molar region of the dental model.

DESCRIPTION OF THE PRIOR ART

Dental articulators are devices used to simulate occlusal andmasticatory motion in dental prostheses that are unique to a particularperson. In particular, the motion to be simulated by the articulatorincludes vertical, lateral and protrusive jaw movements. Recentimprovements in dental model articulators include making the articulatorsystems detachable from the casts to facilitate ease of working on thedental models. Exemplary of prior art patents that address detachabilityof articulator elements from the cast, and that further providestructure that facilitates the occlusal and masticatory motion are thepresent inventor's articulator systems taught in U.S. Pat. Nos.4,382,787, 4,449,930, 4,734,033, and Des. 306,206. The tab cast mount,complemented by the ball and socket structural arrangement and theflexible and detachable hinged structure taught by the foregoing listedprior art patents, greatly facilitate proper alignment of the pairedcasts, and further facilitate the simulation of the paths of naturalocclusal and masticatory registration of the paired dental model casts.However, while the prior art articulator systems have addressed thedetachability and simulation of occlusal and masticatory registration ofpaired dental model casts, the prior art has not fully addressed thesimulation of occlusal and masticatory registration of paired dentalmodel casts where the dental models comprise irregular, or missing teethstructure in the back molar regions of one of the casts. Thisnon-uniform dental model structure results in a vertically unsupportedback molar bite region that frustrates the simulation of verticalmasticatory, or back molar bite movement because vertical movementbeyond a natural occlusal bite position is permitted by the prior artarticulator structures. As a result of the non-uniform bite situation,the prior art articulator systems have resorted to improvised solutionsthat work with the basic articulator system. One such improvisedsolution is shown in FIG. 1, where the illustrated dental articulatorsystem is shown functioning on paired dental model casts having anon-uniform molar region. As shown, a stop rod is utilized to preventtranslational movement beyond the indicated spacing D in the toothlessmolar region between the opposing casts. This step involves having toprepare a cast to receive the stop rod which is fixedly positioned tothe casts to stop the translational movement. This procedure, whilepreventing the undesired translational movement during the masticatoryregistration process, does so, after the situation is encountered, andafter the models have been modified with the stop rod modification. Thisstep is viewed as disruptive and inconvenient during the dental modelregistration process.

Although prior art patents do teach articulators having vertical poststructure located near the back molar regions of the dental model casts,(see generally, U.S. Pat. Nos. 3,092,909, 3,808,689, 4,103,424,4,299,570, 4,865,544 and 5,046,949), these vertical structures are notelements of an articulator system that solve the particular problemaddressed by the present invention, i.e. to facilitate utilization of adental articulator system on paired dental model casts having anon-uniform molar region. Further, these prior art articulators, thatcontain the vertical structures, lack including the widely accepteddetachable and disposable structural characteristics, lack joinablejoint structure that facilitates proper alignment of the paired casts incombination with hinged, flexible structure that facilitate thesimulation of the paths of natural occlusal and masticatory registrationof the paired dental model casts.

Therefore, a need is seen to exist for a dental model articulator thatfacilitates normal utilization on paired dental model casts havingeither uniform, or non-uniform back molar regions, and that is providedin an economical structure that facilitates being a disposable item. Aneed is also seen to exist for a dental model articulator which isfurther provided with structure that facilitates beingmulti-directionally maneuvered to achieve proper alignment of the pairedcasts, that is detachable and hinged to facilitate working on the teethmodels and for simulation of the paths of natural occlusal andmasticatory registration of the paired dental model casts.

SUMMARY OF THE INVENTION

Accordingly, the primary object of the present invention is to providean improved and efficient dental articulator apparatus and method thatfacilitates normal utilization on paired dental model casts havingeither uniform, or non-uniform back molar regions.

Another object of the present invention is to provide an improved dentalarticulator having the above primary object structure that is alsoprovided in an economical structure that facilitates being a disposableitem.

Yet another object of the present invention is to provide an improveddental articulator having the above objects and that also providesstructure that facilitates being multi-directionally maneuvered toachieve proper alignment of the paired casts, that is detachable andhinged to facilitate working on the teeth models and for simulation ofthe paths of natural occlusal and masticatory registration of the paireddental model casts.

The foregoing objects are accomplished by providing a dental articulatorstructure for use in registration of a pair of casts of a dental modelwhich are positioned in an opposing and spaced relationship. In thebroadest embodiment, the articulator structure includes at least oneaxially rigid support member having opposing ends from which joinableand jointed cast attachment members are orthogonally joined, and fromwhich they extend for attachment to respective opposing casts. One ofthe cast attachment members being pivotably detachable from an end ofthe at least one axially rigid support member, and being fixedlyattachable to one of the paired casts of the dental model. The othercast attachment member being fixedly attachable to the other one of thepaired casts of the dental model and extending to, and orthogonallyjoined to the other end of the at least one axially rigid supportmember. The at least one axially rigid support member and theorthogonally joinable cast attachment members being structure thatlocates the axially rigid support member substantially close to the backmolar ends of the opposing pair of dental model casts, such thattranslational movement of the dental model casts is prevented in a planeparallel to the axially rigid support member. Each of the orthogonallyjoinable cast attachment members being preferably formed as a two-piecejoinable structure having a cast attachment end, and a supportattachment end. The two-piece joinable structure that forms the castattachment member has mating curved, partially spherical surfaces(quasi-(ball and socket) configuration) that, prior to being fixedlyjoined, facilitate multi-directional alignment of the pair of opposingdental model casts. The cast attachment members may be formed as atandem structural arrangement that includes the two-piece joinablestructure in combination with at least one spacer block that is usefulfor maintaining an orthogonal relationship between the at least oneaxially rigid support member and both of the cast attachment members andattached dental model casts. In a preferred embodiment, the at least oneaxially rigid support member is formed as a U-shaped structure defininga pair of axially rigid support arms. In use, and at an appropriate castalignment step, the joinable surfaces are adhesively joined. Thedetachable structure facilitates independent cast attachmentmanipulation. The mating surfaces of the two-piece joinable structure,and the spacer blocks are provided with textured surfaces, such as amesh pattern, or grooves, that facilitate the adhesive to wick andachieve a strong bond between the mating surfaces.

Therefore, to the accomplishments of the foregoing objects, theinvention consists of the foregoing features hereinafter fully describedand particularly pointed out in the claims, the accompanying drawingsand the following disclosure describing in detail the invention, suchdrawings and disclosure illustrating but one of the various ways inwhich the invention may be practiced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a dental articulator wherein a stop rod must beutilized to prevent translational movement beyond the indicated spacingD in the toothless molar region between the opposing casts.

FIG. 2 is a perspective view of an embodiment of the present invention,illustrated in an unassembled state and positioned adjacent a pair ofdental model casts that are to undergo initial alignment and subsequentregistration, and also illustrating a U-shaped, two arm embodiment ofthe axially rigid support member having sideways flexing characteristicsthat also facilitates detachability from the cast attachment member.

FIG. 3 is a top view of the present invention showing a tongue andgroove type of alignment and mounting structure for securing the hingedcast attachment member to the upper dental model cast, and alsoillustrating the spherical (multi-directional) type of adjustment madepossible by the joinable surfaces that are part of the two-piece castattachment members.

FIG. 4 is a side view showing the dental model articulator of thepresent invention hingedly and detachably secured to both upper andlower dental model casts and illustrating the preferred close horizontalspacing relationship of the axially rigid support member and theadjacent dental model casts that prevents translational movement beyondthe indicated spacing D in the toothless molar region between theopposing casts.

FIG. 5 is a perspective view showing the dental model articulator of thepresent invention hingedly and detachably secured to both upper andlower dental model casts and illustrating the desired protrusive andsideways flexibility of the articulator structure and the spacing Dwhere translational movement is prevented.

FIG. 6 is a perspective view of a variation of the present inventionshowing a tandem tongue and groove mounting arrangement for attaching tothe upper cast which arrangement includes the two-piece joinable castattachment member, shown in FIGS. 2-5, and (by example) two eatablespacer blocks that facilitate placing the axially rigid support memberin a parallel relationship with the back end of the dental model casts,and in a preferred orthogonal relationship with the assemblage referredto as cast attachment members.

FIG. 7 is a side view, showing the embodiment depicted in FIG. 6 fullyassembled with all joinable surfaces adhesively bonded, illustrating thespacing D where movement is prevented by the axially rigid supportmember, and further illustrating the tandem tongue and groove mountingarrangement of the spacer blocks with the two-piece cast attachmentmembers that facilitate placing the axially rigid support member closeto, and in parallel relationship with the back end of the attached cast,and in an orthogonal relationship with the cast attachment members.

FIG. 8 is a bottom view of the dental model cast depicted in FIGS. 6 and7 illustrating the use of only the two-piece cast attachment member, andfurther showing the support attachment end of the two-piece structure asbeing integral with bottom cross member of the U-shaped axially rigidsupport member.

FIG. 9 is an enlarged view of the upper cast portion showing the hingedopen end of the axially rigid support member, and the tandem structuralarrangement of the spacers and the two-piece cast attachment member,which together form a composite, jointed cast attachment memberstructure. The composite structure being facilitated by the tongue andgroove mating structure of the spacers and the curved spherical matingsurfaces of the two-piece cast attachment member.

FIG. 10 is an enlarged perspective view of the spacer illustrating thetongue and groove structure, showing as well, the wicking grooves thathelp achieve a strong adhesive bond during an assembly step.

DESCRIPTION OF THE PREFERRED EMBODIMENT

As discussed previously, FIG. 1 illustrates a prior art dentalarticulator system 10 wherein a stop rod 20 must be utilized to preventtranslational movement A1 beyond the indicated spacing D in thetoothless molar region 42 between the opposing casts 30, 40. FIG. 2shows dental articulator apparatus 100, designed according to theprimary object of the present invention. Articulator 100 provides asolution that eliminates having to perform the step of placing a stop,such as stop rod 20, to prevent the translational movement A1 on dentalmodel casts 30,40 having a toothless molar region, such as region 42depicted in FIG. 1. As illustrated, articulator 100 is positionedadjacent a pair of dental model casts 30,40 that are to undergo initialalignment and subsequent registration. Articulator 100 is preferablyformed from a disposable plastic material and includes, in the preferredembodiment, a U-shaped body, referred to as the axially rigid supportmember 110, having axially rigid arms 112, 113 that have sidewaysflexing characteristics that facilitate detachability from the uppercast attachment member 130. While articulator 100 is formed as aU-shaped structure, a single axially rigid support member, or otherequivalent axially rigid structure is considered within the scope of theinvention. Thus, as depicted in FIG. 2, articulator structure 100includes two axially rigid support members, or arms 112, 113 havingrespective opposing ends from which joinable and jointed cast attachmentmembers 120, 130 are orthogonally joined, and from which members 120,130 extend for attachment to the back ends 31, 41 of respective opposingcasts 30, 40. Cast attachment member 130 is shown pivotably attachableat a pivot 140. By example, pivot 140 is facilitated by holes 111, atthe upper end of each of the arms 112, 113, that detachably mate withpin shafts 136 formed on the support attachment end 137 of member 130.As depicted in FIG. 2, each of the orthogonally joinable cast attachmentmembers 120, 130 are preferably formed as two-piece joinable structures(122,124), (132,134), respectively, each having respective castattachment ends 121, 131, and respective support attachment ends 126,137. The two-piece joinable structures (122,124), (132,134) that formthe cast attachment member 120, 130, have mating curved, partiallyspherical surfaces (123,125), (133,135) that, prior to being fixedlyjoined, facilitate multi-directional alignment, depicted by arrow A4 inFIG. 3 and by arrow A5 in FIG. 2.

It should be noted that, although casts 30,40 are herein provided havinga toothless molar region 42 in the back part of the models, the presentinvention will function on dental models that have uniform teethstructures. The initial alignment of the dental model casts 30,40 iseffected according to well known techniques in the art, and ultimatelylead to the step of attaching the casts to the particular articulator tobe employed for simulating the occlusal and masticatory motion. In thepresent invention, and by example only, the back face of casts 30, 40are adapted with grooved ends 31, 41 having slots or grooves 51 and 61for receiving tabs or tongues 121, 131 on attachment portions, or mounts122, 132. FIG. 3 shows the alignment A3 made possible by the combinedtongue and groove structures (51,131) for positioning the mount 132 tothe upper cast 30. The attachment of mount 122 to the lower cast 40 issimilarly effected, see FIG. 4 showing groove 61 mated with tongue 121.The cast mount portions 122, 132 are fixedly attachable to casts 30,40using adhesives, such as the prefired fast setting cyanoacrylate oraerobic adhesive. Wicking grooves on cast 30, 40 may be employed, asillustrated and taught by the present inventor in U.S. Pat. Nos. Des.302,725 and 4,734,033, to improve the cast-to-mount bond.

Once mounts 122,132 are fixedly attached to casts 30, 40, the supportmember attachment portions 124,134 of the cast attachment assemblies120,130 are adhesively joined to mounts 122,132 after appropriatealignment as indicated by arrows A4 and A5 in FIGS. 2 and 3. In thepreferred embodiment, support attachment portion 134 is an independentpiece having pin shafts 136 at an end 137, and spherical surface 135 atthe other end. Attachment portion 124 is formed integral with, andintegrally interconnects arms 112, 113 at an end 126 and is providedwith a spherical surface 125 at an opposing end. As noted above,portions (122,124) and (132,134) are formed to facilitate motionindicated by arrows A4 and A5 for aligning the casts and thus, areformed, as noted above, having partially spherical, joinable surfaces(123,125), (133,135), respectively. By example only, surfaces 123,133are formed concave and surfaces 125,135 are formed convex. Afterdetermining the final orientation of the casts 30,40 and the desiredplacement of the articulator 100, surfaces (123,125) and (133,135) areadhesively joined to form joints 150, 160, respectively, see generallyFIGS. 3, 4, 5. The formation of joints 150, 160 completes assembly ofrespective upper and lower jaw models.

In accordance with the primary object of the present invention, thedistance depicted as Hs in FIGS. 3 and 4 is determined by the length ofcast attachment members 120, 130, and is preferably kept to a minimum(preferable range 0.40 to 0.75 inches more preferably 0.50 to 0.75inches) to assure that axially rigid support member 110 (112,113) areclosely attached in a parallel spaced relationship with the back facesof opposing dental model casts 30, 40. The close spacing relationshipHs, in combination with the axially rigid structure of support 110(112,113), assures that translational movement is prevented in the spacedepicted by the letter D in FIG. 4.

According to another object of the present invention, upper and lowerjaws are hingedly and detachably secure at pivot 140, see generally FIG.4 showing hinge action arrow A2., and FIG. 3 showing pivot 140 (111,136)at an upper end 110A of arms 112, 113. FIG. 5 is a perspective viewshowing the dental model articulator 100 hingedly and detachably securedto upper dental model cast 30 at pivot 140 (111,136) located at an upperend 110A of arms 112,113. Cast attachment member 130 (132,134) is shownas a two-piece structure joined at joint 150 (133,135) and being fixedlyattached at tongue and groove joint formed by members 131,51, see alsoFIG. 4. Thus, cast attachment member 130 (FIG. 2) is pivotablydetachable from a first distal end 110A of axially rigid support member110 and fixedly attachable to cast 30. The angular relationship betweencast attachment member 130, having cast 30 attached, and axially rigidsupport member 110 is preferably orthogonal. However, the particularalignment and registration requirements that result in the best bite forthe particular dental model being simulated will determine the finaladhesive fixation that forms joint 150.

The fixation of joint 150 is also related to the fixation of joint 160for the lower cast 40 during the alignment process. As previouslydiscussed, the lower cast attachment member 120 comprises attachmentportion 124 that is integral with the axially rigid support arms112,113. FIG. 5 shows arms 112, 113 being interconnected by attachmentportion 124 at an end 110B opposite open end 110A, and also shows thespherical surface 125 joined with mating curved surface 123 to formjoint 160. The shape of surface 123 of cast attachment portion 122 ispreferably an elongated, concave, channel-like curved structure thatfacilitates convex spherical surface 125 having multi-alignmentcapability before being adhesively fixed to form joint 160. The shapesof surfaces 133,135 are similar and provide the same multi-alignmentcapability before forming joint 150. Thus, cast attachment member 120 isfixedly attachable to cast 40 and extends from a distal end 110B ofaxially rigid support member 110.

FIG. 5 also illustrates the primary object of the present invention,i.e. that the axially rigid construction of arms 112,113, in conjunctionwith the close spacing relationship Hs between the arms and the backface of the cast, (best seen in FIGS. 3 and 4), assures thattranslational movement is prevented in the spacing D about the region42. Notwithstanding the axially rigid construction of arms 112,113, FIG.5 also illustrates that articulator 100 is also constructed forfacilitating the protrusive and sideways flexibility characteristicsthat are desirable in an articulator system. The flexible is generallyindicated by flexing motion arrows F1, F2, and F3.

The flexing motion is facilitated by the arms 112 and 113 being spacedapart substantially vertically extending struts that provide torsionalresponse to pressure to simulate the articulation of a patient's jawmovement as illustrated by direction indicating arrows F1, F2 and F3 andthe directions in between. Thus, arms 112 and 113 are torsion responsestruts that are the sole suspending supports of the upper or top modelcast 30 in contact with the lower stationary model cast 40. The struts112 and 113 should be substantially completely relaxed and substantiallyfree of torsional tension when the teeth of the model casts 30 and 40are in their fully occluded positions.

For preferred action, and simplicity of construction, in one preferredembodiment, there are two spaced apart struts positioned substantiallyat the outermost one side of articulator 100 with the upper and lowerrespective model cast mounts 134 and 124 extending away therefrom andprojecting in substantially common directions at substantially rightangles from the struts to positions of securement to respective modelcasts 30 and 40 via adjustable connectors, i.e. dental model castmounting blocks 132 and 122 respectively. In some embodiments it may bepreferable to split each strut, or form other multiples of spacedstruts. Of course, in addition, in some situations a center strut may bedesirable at the side of articulator 100 from which the model castmounts project. Generally, a single strut provides less preferredtorsional properties, but an articulator with a single arm mayadvantageously provide the other advantages of the present inventionfully.

To provide the desired torsional properties in the preferred embodimentdepicted in FIGS. 2-5, the arms 112 and 113 are preferable injectedmolded from plastic, preferably thermoplastic or thermosetting plasticsthat are not brittle after polymerization and forming and/or shaping.The most preferred plastic is thermoplastic and preferably class 66thermoplastic. The exemplary embodiment illustrated was formed of class66, Vytel 10L thermoplastic available from Dupont Corporation. Thesupport attachment portions of the dental model cast mounting blocks 122and 123 are preferably made of the same plastic as the arms 112 and 113,as are the spacers 210 and the articulator cast mounts 124 and 134.

Each arm 112 and 113 preferably has a height extending 1.50 to 1.80inches, more preferably 1.60 to 1.75 inches above the top surface of thelower articulator cast mount 124, each arm having a cross sectionaldimension of preferably 0.12 by 0.18 inches, more preferably 0.125 to0.188 inches. The height of the arms is measured to their outer top tipsand the holes, or pin shafts 136 for the pivots are centered and arepreferably 0.03 to 0.05 inches below the tips of the arms in theexemplary embodiment.

For the best torsion response, struts, or arms 112 and 113, in apreferred embodiment, will have a breadth dimension, in the direction ofthe projection of the model cast mounts 134 and 124, which is thedirection of the arrow F1, that is greater (preferably 11/2 timesgreater) than the width dimension which is the direction indicated bythe arrow A4. Further, in a preferred embodiment the articulator 100 hasarms 112 and 113 that are of substantially uniform dimension, i.e. widthand breadth between the base mount 124 and their tips. These featuresare important in providing optimum simulation of masticating, as well asother movements to which a denture may be subjected to during use.

Preferably, the arms 112 and 113 should be within 1.0 to 1.2 inches,more preferably 1.0 to 1.125 inches of the nearest extent of the molarregion of the model cast. The arms 112 and 113 are spaced apart 1.2 to1.3 inches, more preferably 1.20 to 1.30 inches. This approximates theaverage spacing of the molar regions at the rear of arches of upper andlower dental model casts 30 and 40. This spacing aids in simulating thenatural hinging of the human jaw. It will be noted that this positionsthe torsional response struts 112 and 113 within the usual widthdimension of the dental model cast. In other words, the cast is normallywider than articulator 100.

The lower and upper support attachment portions, 122 and 132, areforward projecting dental model cast connectors and have respectivecross sections of 0.4 by 0.5, more preferably 0.40 to 0.60 inches in thedirection of arrow A5 in FIG. 2 and a width of 1.20 to 1.30, morepreferably 1.245 to 1.255 inches in the direction of arrow F2 in FIG. 5.In horizonal extent, the convex curvature of the face of articulatorcast mounts 124 and 134 and the concave curvature of joinable mounts 122and 132 is preferably between 1.20 and 1.75 inches, more preferably1.245 and 1.255 inches, and the preferred radiuses are 1.4 to 1.6inches, more preferably 1.45 to 1.55 inches. While preferably the facesare portions of an evenly progressing circle, in some embodiments theycan be elliptical, for example.

It will be observed that the lower face of the cast 40 in FIG. 5 isintended to sit on the work support surface or table and the articulator100 is suspended in the preferred configuration. This is a preferredmethod of achieving the vertical relationship for articulation. It ispreferred that the concave faces of the joinable mounts 122 and 132 havethe greater perpendicular vertical extents, preferably 0.55 to 0.70inches, more preferably 0.61 to 0.64 inches and that the convex faces ofthe articulator mounts 124 and 134 have lesser perpendicular verticalextents, preferably 0.22 to 0.26 inches, more preferably 0.24 to 0.25inches to facilitate selecting a wide range of fixation location alongarrow A5. Also, the convex faces 123,133 of articulator mounts 124 and134 have a vertical curvature of 1.45 to 1.55 inches. Vertical surfaces125,135 do not have a vertical curvature to facilitate being selectivelyfixed along the convex faces 123, 133, along arrow A5. While the termsupper and lower and horizontal and vertical have been used, theseobviously refer to direction when the articulator is oriented in uprightposition.

The preferred plastic construction of articulator 100 results inrealizing another object of the present invention, namely to provide animproved, economical dental articulator structure that facilitates beinga disposable item.

FIG. 6 is a perspective view of an alternative dental articulatorembodiment 200 of the present invention. Embodiment 200 satisfies inevery respect the objects of the present invention. Notable structuralvariation include a tandem tongue and groove mounting arrangement 130A(see FIG. 9) for attaching to upper cast 30. The tandem arrangement 130Aincludes the two-piece joinable cast attachment members 132,134,(previously discussed and shown in FIGS. 2-5), and, by example, twomatable spacer blocks 210. In this particular embodiment 200, the lowercast 40 is attached using similar pieces as used for embodiment 100, seeFIGS. 7 and 8. The utilization of spacers 210 depends upon the relativealignment of the back faces of the opposing cast 30,40 during an initialalignment step. The relative alignment is a factor of the initialplacement of the teeth models on the raw casts. Thus, a technician canselect the number of spacers 210 needed for the task at hand tocompensate for the cast's back face offset, and to assure that theaxially rigid support member 110 is in a substantial orthogonalrelationship with the assemblage referred to as cast attachment members120,130, and also to minimize the spacing Hs, (see generally FIG. 7showing angle A being substantially at 90 degrees and Hs). The resultingarticulator structure is axially rigid along the longitudinal axis ofarms 112,113 and prevents translational movement into the toothlessregion 42 and spacing D, see FIG. 7. Pivot 140 (111,136) facilitateshinge action of cast 30,40 a well as detachment of the casts 30,40 fromeach other.

Joints 150 and 160 are formed after selecting a final alignmentlocation, as previously discussed. However, the adhesive bonding isimproved by texturing the surfaces (123,125) and (133,135). Thetexturing T1 is shown, by example, in a mesh pattern. Joints 150, 160are enhanced by constructing surfaces 125 and 135 having a sphericalradius R (approx. 1.5 inches) for producing better alignment and contactwith mating surfaces 123, 135, see FIG. 9. FIG. 9 also shows shelf 114on the upper end of arms 112,113 for limiting rotation A6 during aninitial alignment involving support member attachment portion 134. Theinitial step of attaching to the cast differs from embodiment 100 inthat a spacer 210 is mounted to the groove 41, employing a tongue 212provided as part of the spacer structure, see FIG. 10. Spacer 210 isalso provided with a groove 211 that is similar to groove 41 and isdesigned to mate with either tongue 212 or 131. Groove 211 facilitatesthe use of another similar spacer 210 to extend the reach and accomplishthe desired articulator mounting objective. Spacer 210 is also texturedabout the groove area to provide improved wicking action of the adhesiveused to form the tongue and groove joints 220 (131,211), 230 (211,212)and 240 (31,212), see FIG. 9. The texturing T2 is formed as wickinggrooves that feed into the groove structure 211, see FIG. 10.

To use the articulator 100, slots 51 and 61 are cut or formed disposedhorizontally in respective substantially flat planar surfaces at oneside, ends 31 and 41, of dental model cast 30 and 40. The ends 31 and 41extend substantially perpendicularly to the back of the arch of the setof teeth and are perpendicular in vertical extent.

Next, the area of each respective dental model cast 30 and 40, includingthe areas of the slots and of the flat faces of respective ends 31 and41 adjacent to the slots 51 and 61 that are to be contacted by the castmounting blocks are coated with an adhesive, preferably the fast settingcyanoacrylate adhesive, commercially available from KV33 Corporationunder the brandname VERTEX Adhesive, Super Thin cyanoacrylate adhesive.The respective tongues 121 and 131 and adjacent planar flat faces of thecast mounting blocks that are to contact the coated areas of the dentalmodel casts are then preferably coated respectively with the sameadhesive and brought into engagement with respective coated areas of thedental model casts and adhesive is set by spraying the adhesiveaccelerator, or initiator, commercially available from KV33 Corporationunder the brandname VERTEX Accelerator on the cyanoacrylate interfacearea to set the adhesive and freeze in position the mounting. Thissecures the respective parts firmly together. It will be understood thatthe tongues 121 and 131 are preferably sized to engage against theinside of slots 61 and 51, respectively, and be adhesively securedtherein.

After the dental model casts 40 and 30 have been secured to respectivecast mounting blocks 122 and 132 they are typically ready to be mountedto articulator 100. In a preferred procedure, the dental model casts 40and 30 are placed in occlusion and the concave textured faces 123 and133 of respective cast mounting blocks 122 an 132 are coated withcyanoacrylate adhesive. The respective textured convex faces 125 and 135of the articulator cast mounts 124 and 134 of articulator 100 are coatedwith cyanoacrylate adhesive and the respective faces 123 and 125 and 133and 135 are brought into interface contact and aligned horizontally andvertically so that when frozen, or set by the setting of thecyanoacrylate adhesive, the cast 40 will set substantially level on theflat table surface with the teeth of casts 40 and 30 in occlusion withstruts 112 and 113 vertical and the articulator 100 substantiallycompletely free of torsional stress as illustrated in FIG. 5. Then theadhesive accelerator, or initiator is sprayed on the cyanoacrylateinterface areas to set the adhesive and set, or freeze the construction.

Articulation can then be carried out in conventional manner through thetorsional stressing of struts 112 and 113 to simulate normal jawmovements of a patient. The upper cast 30 may be removed for betteraccess by pushing the tips of the struts toward one another asillustrated in FIG. 2.

When the dental model cast assembled, with the cast mounting blocks, arenot going to provide a proper at-rest articulation occlusion position,as determined either by, unadhered preassembly of the parts, or justtrained-eye observation, spacer block 210 can be added, as clearlyillustrated in FIGS. 6,7 and 9 to adjust the positions. The articulatorspacer block 210 has two outwardly facing sides, a tongue 212 may beseen to project from one side, and groove, or slot 211, projectsinwardly from the opposite side. Four walls disposed at substantially90° from the planar face surrounding the slot penetrated into the block210 to from the slot. A plurality of channel wicking grooves are formedin the planar face and extend to at least near the inner most extent oftwo of the penetrating walls that form the slot. This aids in goodadhesive distribution and adherence. The slots 211 are sized to receivetongues 212 so that spacer blocks 210 can be built up as illustrated.

Therefore, while the present invention has been shown and describedherein in what is believed to be the most practical and preferredembodiments, it is recognized that departures can be made therefromwithin the scope of the invention, which is therefore not to be limitedto the details disclosed herein but is to be accorded the full scope ofthe claims so as to embrace any and all equivalent apparatus.

I claim:
 1. A dental articulator comprising:a first and a secondflexible torsion response strut, said torsion response struts spacedapart, substantially parallel to one another, each connected at onerespective end to a first dental model cast connector that projects awayfrom them at substantially a 90° angle and connected at their otherrespective ends to a second dental model cast connector that projectsaway from them at substantially a 90° angle, the first and second dentalmodel cast connectors being oriented so that they will be substantiallyaligned with one another when upper and lower dental model casts arerespectively engaged with them and in at rest occlusion, wherein saidfirst dental model cast connector has a convex face extending atsubstantially a 90° angle from said projection of said dental model castconnector with a radius of 1.45 to 1.55 inches and a curvature radius of1.45 to 1.55 inches.
 2. The dental articulator of claim 1 wherein:saidstruts are spaced apart from 1.245 to 1.255 inches and each has a crosssection between 0.188 and 0.125 inches in any dimension.
 3. The dentalarticulator of claim 2 wherein:said first and said second torsionresponse struts are the only means securing said upper and said lowerconnectors together.
 4. The dental articulator of claim 2 wherein:saidfirst and said second torsion response struts are integral with saidlower connector and said upper connector is connected to said first andsaid second torsion response struts with pivot connections.
 5. Thedental articulator of claim 4 wherein:said struts are spaced apart from1.245 to 1.255 inches, and have a width of 0.120 to 0.130 inches and abreadth of 0.185 to 0.190 inches and a height of 1.65 to 1.70 inchesfrom the top surface of the lower connector to their tips and saidstruts and connectors comprising class 66 thermoplastic.
 6. The dentalarticulator of claim 1 further comprising:a dental model cast mountingblock having a face that is concave and being adhesively connecteddirectly to said convex face of said first dental model cast connector,the said concave and convex face curvatures matching, providing a goodinterface contact.